Thread-cutting machine.



H. R. FARNSWORTH.

THREAD CUTTING MACHINE.

APPLICATION FILED DEG. 5, 1907.

4 SHEBT88H EET 2.

Patented Apr. 9, 1912.

B wwwg i n" s 8% ma a a H. R. FARNSWORTH.

THREAD CUTTING MACHINE.

IIIIIIIIIIIIIIIIIIIIIIIII 7.

60 g E li i- .i 4 Z Fag 1 AllameyJ,

H. R. FARNSWORTH, THREAD CUTTING MACHINE.

APPLIDATIDH TILED DEC. 5, 1907.

Patented Apr. 9, 1912.

w a 9 ,0 w m z a 4 III H 1 9 I 0.0 J 0, x Mow w i 7 1 w s w 1 w\ r iUNITED STATES PATENT OFFICE.

HILAND R. FARNSWORTH, OF SANDUSKY, OHIO, ASSIGNOR- TO THE SANDUSKYFOUNDRY &. MACHINE COMPANY, OF SANDUSKY, OHIO, A CORPORATION OF OHIO.

THREAD-CUTTING MACHINE.

To all whom it may concern.

Be it known that I, HILAND R. FARNS- wolrrn, a. citizen of the UnitedStates, residing at Sandusky, in the county of Erie and State of Ohio.have invented certain new and useful Improvements in Thread-CuttingMachines; and I do hereby declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same.

The object of this invention is to provide screw-tlnrcading and tappingmachines with improved means for retracting the threadcutting dies fromthe work, on completion of the operation, and for returning said dies tooperative position when the die-carrying head is reversed or turned backto starting position. These well-understood functions are, by my presentimprovement, performed in a very simple way, and by utilizing only theessential elements already existing in the machines to which theinvention is or may be applied.

In the accompanying drawings, which form a part of this specification,the invention is shown as applied to a number of machines of varioustypes, to disclose the universality of its application, from which itwill be clear that the range of adaptation of the invention is to be inno wise restricted to the particular machines illustrated in saiddrawings.

he inventicn will be first fully described by reference to said drawingsand then more particularly pointed out in the claims following thisdescription.

Figure 1 discloses a preferred embodiment of my invention, applied tothe improved pipe-threading machine invented by Mr. A. L. Robbins. anddisclosed in his Patent No. 887.741. dated May 12, 1908. This figureshows the machine in central vertical section. and representing the diesin operatire or work-engaging position, and ready to start theoperation. Fig. 2 is a similar fragmentary view of the same machine,with the die in retracted or work-releasing posi- Specification ofLetters Patent.

Application filed December 5, 1907.

Patented Apr. 9, 1912.

Serial No. 405,276.

tion. In this figure, the pipe which has been threaded is indicated bydotted lines. Fig. 3 is a perspective view of one of the dies. Fig. 4 isa fragmentary view similar to Fig. 1,illustrating another form orembodiment of my improvement. Fig. 5 is a perspective view of the dieshown in Fig. 4. Fig. 6 is a view similar to Fig. 4, showing stillanother form or embodiment of my improvement. Fig. 7 is a fragmentarysectional view of a pipe-threading machine of the type shown in patentto Vosper No. 763,816 dated June 28, 1904, illustrating an applicationof my invention thereto. Fig. 8 is a perspective view of one of the diesused in this latter form of machine. Fig. 9 is a fragmentary sectional.view of a pipe-threading machine of the type shown in patent to CableNo. 828,016 dated August 7, 1906, illustrating an application of myinvention thereto. Fig. 10 is a. top plan view, partly in section, ofthe same. Fig. 11 is a. view similar to Fig. 9, showing a modifiedembodiment of the invention in. the Cable type of machine. Fig. 12 is acentral sectional view, partly in elevation, of a. tapping machineshowing an application thereto.

Referring first to Figs. 1, 2 and 3, in which my invention is shownapplied to the Robbins pipe-threading machine, the symbol 1 denotes thehollow body or casing of said machine. constituting the stationary frameor work-holder thereof, in the neck of which the pipe, rod or otherobject to be threaded (called the work) can be centered and clamped bymeans of the set-screws 4. In the tubular part 2 of said work-holder,the internal lead-screw 3 is engaged by the tubular feed-screw G of theannular diestock or die-carrying head 5; whereby. as the die-stock orhead is revolved to carry out the thread-cutting-operation. whichrevolving may be effected in any appropriate manner, the die-stock orhead is caused to advance axially within the casing or workholder. It isunderstood of course that either the work or the dies may be revolved,the movement being relative. though in practice it is usual to revolvethe die'carry' ing head. The radially-movable threadcutting dies orchasers 8, slidably-fitted in guide-ways or slots 7 therefor in thehead, and equipped if desired with the usual means for limiting theirinward movements, are provided at their inner ends with thethreading-bits 9, while their outer ends, or backs of the dies, whichproject beyond the perimeter of the die-head, contact with an abutment,consisting here of an interiorly tapered or conical sleeve or annulus10, revolubly seated in the casing 1, being retained in position thereinby a retaining-ring 11 which in turn is secured in place by screws 12 orother suitable fastenings. It may be noted that the backs of the diesare herein shown slightly rounded transversely, as seen more clearly inFig. 3, so as to bear with a minimum amount of friction against theconical ring or tapered sleeve 10 which, it will be understood, revolveswith the dies and is tracked or traversed longitudinally by the latteras the work advances, allowing a gradual receding of the dies asrequired to cut a tapered thread, as indicated in Fig. 2, according tothe Robbins invention. As explained in said Robbins patent, the sleeve10 is revolved with the dies either by the pressure of the latteragainst said sleeve, or by any suitable feather and groove connectionbetween the sleeve and die head.

The foregoing parts, except as hereinafter noted, are or may besubstantially similar in form and operation with the corresponding partsdisclosed in the Robbins patent above mentioned; but it should be addedthat, for the purposes of my present invention, it is immaterial whetherthe abutment member 10 be tapered or cylindrical, or whether it revolvewith the dies or not (though of course it is far preferable to have saidmember revolve with the dies) and, furthermore, said member may bedispensed with and the dies arranged to abut directly against theinterior of the casing 1. in which event the latter would have a smoothinterior surface, either cylindrical or tapered; it being expresslyunderstood that the present showing and description of the Robbinsmachine is for the purpose of exemplifying one adaptation of myinvention to a machine of that character. For the purpose of myinvention, therefore, the conical abutment mem ber 10, which is actuallya separate element for the purpose of providing a revoluble conicalabutment for the dies, may be considered as a part of the casing 1. Theseveral modifications above suggested will he made apparent by referenceto other figures of the drawings hereinafter.

So much for a brief exposition of the obbins machine. 1 will now explainan application of my invention thereto.

In accordance with my invention, the inner or lower end of the sleeve 10is inwardly beveled or chamfered at 13, while opposite or below the samean annular flange l t in the casing 1 has its upper end outwardlybeveled or chamfered at 15, the slant of the latter bevel 15 beingpreferably substantially parallel with that of the bevel 13. These twobevels or inclines or cam-surfaces 13 and 15 provide between them aspace or recess 16, which (bearing in mind that the invention is beingdescribed with reference to the Robbins machine) is annular and extendswholly around the casing. Said annular space 16 is adapted to admit thebacks of the dies 8 when retracted, as will appear later. Openings 1?cut at intervals in the casing 1 are merely to allow escape of chips ormetal cuttings and reduce material. The backs or outer ends of the diesare beveled on their upper edges at 18, for coaction with the bevel 13to return the dies after retraction; while the dies are also made orprovided in some suitable manner, as by recessing their under facestransversely, at 19, with projections 20 whose inner faces are beveledat 21 for eoaction with the bevel 15 to retract the dies.

In operation, the pipe or other object to be threaded being clamped inthe workholder, and the die-carrying head starting at or about theposition shown in Fig. 1, with the dies in operative or \vorlcengagingposition, the die-head in lOVOlVlUg is advanced axially, causing thedies to perform the thread-cutting operation in the usual way: in thisinstance the thread being cut on a. taper (as indicated by the dottedline representations of the pipe in Fig. 2) by virtue of the conicalinterior surface of the member 10 against which the backs of the diesabut. As the die-head reaches the limit of its feed-movement, that is oncompletion of the thread-cutting operation, the bevels 21 on the undersides of the dies engage and ride upon the annular bevel 15, therebyautomatically retracting the dies from the work, moving them to theposition shown in Fig. 2, with the back portions of the dies seated inthe annular recess 16. 1h this position, the bevels 18 on the uppersides of the dies may lie against or near the bevel 13 on the lower endof the sleeve 10. The dies having thus been retracted, as explained forrelcasing the work, the latter is removed from the work-holder, and thedie lu-ad reverselyrevolved to feed it to its initial position. At thebeginning of this return movement of the die-stock, the bevel l3)courting with the beveled faces 18 on the dies will automatically returnthem to their operative position; the dies as they move from the annularrecess 16 being also carried upwardly by the reverse feed of the stockand thus brought in contact with the interior surface of the member 10as before. The

only one is shown) is an abutment pin or block 51 having at its innerface, which is opposed to the back of the adjacent die 18. a groove orchannel 52 annular with respect to the die-carrier made to receive theouter end of the die or chaser, and provided with an inclined face orwall for guiding the die in cutting the tapered thread on the work.

In adapting my invention to this Cable machine, and as shown in Figs. 9and 10, the abutment wall 53 of the pin 51 is beveled at its end to forman inclined cam face 51, while below the same, and fixed thereto bymeans of a dowel 55, is a supplemental piece 56, constituting acontinuation of the pin, and suitably recessed to form an upwardlyprojectingportion or finger 57, having an inclined bevel or cam face 58,which cooperates with the correspondingly inclined cam face 59 on thedie or chaser for retracting the latter to inactive or wo1'kreleasingposi* tion; a cam face 60 being formed on the die to cooperate with thecam face 5 1, for moving the die to active or work-engaging position. Inthe operation of this form of device, when the die-stock -15, whichrotates in unison with the casing 49, reaches the limit of its feedmovement, or that is at. the completion of the thread forming operation,the bevel or cam face 58, through engagement with the bevel or cam face:39, retracts the die into the recess and out of engagement with thework, which may then be removed from the work-holder prior to returningthe die-stock to its initial position; and, at the beginning of thereverse movement of the (liestock, the bevel 60 will ride on the bevel51!; for throwing the die to active or work-engaging position. Except inthe formation of the guide-pin 51, and the outer end of the die orchaser, as explained. the construction and operation of the machine maybe the same as disclosed in the aforesaid (able patent.

In Fig. 11, illustrating a modification o'l Fig. 9. he guidepin 51 isprovided, in lieu of the beveled projection 5T, with a pin 01 extendedtransversely through the guide-pin between the walls of theguide-channel 2, which is continued below the cam face 5-1: and in theoperation of the device, the pin (31. arts as a cam for engagement withthe bevel or cam-face 59 on the die or cha er 8, for throwing the latterto inactive or work-releasing position. In all other rcspects theconstruction and operation of Fig. ll corre poml to the de cription ofFig 9 and 10.

Fig. l), which represents an application of my invention lo a tappingmachine, may be briefly explained as follows: 95 denotes the verticalspindle of a standard or any well known type of drill-press, the power.feeding and adjusting mechanism of which is not shown. 96 is a.stationary bearing for the drill-spindle. 97 is the bed or platen of thedrill-press, and 98 are raised ribs or parallels thereon. 99 denotes anannular casting, such as a pipe-flange, which is to be tapped orinteriorly threaded. This circular casting of course properly centeredand clamped upon the bed. In the nose of the drill-spindle. there isshown fitted the well known Morse tool-shank 100, which instead of beingprovided with a drill-bit carries in this case a cone 101. Said cone 101has at its lower and smaller end a contracted or reduced extensionterminating in a bottom flange 102. The lower end of the cone proper andthe flange 102 are shaped to provide opposed bevels 103 and 101, betweenwhich is a recess 10.3. Surrounding the cone is an annular diehead 100,carrying in slots therein a series of radially movable tapping dies 104-for engaging and interiorly threading the hole in the casting 99; thethreading bits of the dies being of course at their outer instead oftheir inner ends. The backs or in this case the inner ends of the diesabut against the cone 101 and engage in vertical grooves or channels 108in the latter. Said backs of the dies are also made to fit within oradapted to enter the aforesaid recess 105, and are formed with thebevels 109 and 110 for coaction with the bevels 103 and 104respectively. Said dielie'ad has a tubular extension 111 which looselyencircles the nose of lhedrill-spindle. To prevent the die-head fromfalling olf when the drill spindle is lifted up, a spring pressedplunger 112 in the tubular part or sleeve 111 bears frictionallyagainst. the side of the drill-spindle. Further, when the drill-spindlcis raised, the dieholder may be retained by a. hook 113 engaging in anotch-like groove 114 in the tubular part 111. said hook being attachedby a clamp or otherwise to the bearing 96. The hook is shown released inthe drawing. for the reason that big. 9 represents the. mechanismlowered to operative position for engaging the work. lnside the tubularextension 111 of the die-head is a ring 115 constituting an abutment forthe lower end or nose of the drill-spindle. This ring may be adjusted byscrewing it in an internally threaded portion 110 of the sleeve 111, andsecured by a set screw 11? the purpose of which will be explained later.

The operation as follows: After the casting 99 to be tapped is fixedupon the bed or platen. then the drillspindle is. by means of theadjusting or feeding mechanism of the drilbpress, hiwered to workingposition. carrying with it the cone 101 and the dioholdcr 100, thelatter having been first released from the hook 113. The drillspindle islowered until the dies are brought down to the work, in position toproceed with the operation, as shown in Fig. 12; the

nose of the drill-spindle abutting the ring 115 in the die-holder. Thedownward movement of the drill-spindle is now stopped, and power isapplied to revolve the spindle, but without feeding it downward. As thespindle revolves. the die-head will also revolve, since the backs orinner ends of the dies are engaged by the channels 108 of the cone 101,the latter being of course revolved with the spindle. This revolving ofthe die-head will cause it to feed downward to carry out the tappingoperation, the backs of the dies moving downward in the channels 108 andin contact with the cone 101, which allows the dies to recede graduallyfor making a tapered thread. If a straight thread is desired, theelement 101 would of course be a cylinder. The feed of the dies isefi'ected by their own screw-cutting action. As the dies reach the limitof their feed movement, the bevel 101 will engage and coact with thebevels 110 and thereby retract the dies. Thereupon the drill-spindlewith the parts carried thereby can be raised to release the work andpermit its removal from the machine; and another casting can be securedin place for tapping. The drill spindle is then lowered as before tostart the operation on the next casting, and as the dieholder assumesits initial relative position, the nose of the drill-spindle beingbrought. again against the abutment 115, the bevel 103 will engage andcoact with the bevels 109, and thus reset the dies. It is noted that theposition of the ring 115 will determine the relative positions of thecone 101 and die-head at the beginning of the tapping operation. By theadjustment of said ring 115, as previously mentioned. the relativeposition of the cone may be so effected as to provide for tapping holesof larger or lesser diameter, without changing the dies, since theinitial position of the cone relative to the dies will of coursedetermine the size of the thread which to be cut. Again, where using thetapered cone 101. the cone and die-holder may be locked together and feddownward in unison. and the cone may be utilized for adjusting the diesto vary the diameter of the thread which is cut, means being providedfor bringing the bevels into coaction at the completion of the operationfor retracting the dies from the work, on the principle explained. It.is understood of course that the mechanism shown in this Fig. 12 ismerely to ex emplify one suitable application of my invention to atapping machine.

In the following claims, the terms "rctractable and backs of the dies.as well as other similar or related terms. are to be I construed withreference to the particular type of machine to which the invention maybe applied: it being apparent that the dies retract outwardly in thecase of a pipe threading or rod-threading machine, whereas they retractinwardly in the case of a tapping machine.

The term revoluble as applied to the die-stock will be understood asused in a relative sense, and as applying equally to a constructionwhere the work is revolved in a stationary die-head. The term radial isnot used restrictively butis intended to apply also where the dies maybe disposed more or obliquely to strictly radial lines.

It will be observed that in each of the illustrated embodiments of theinvention there a frame, which may consist of a single member having theworkholder at cue end thereof, or of the work-holder and a memberrevolubly mounted thereon; said frame having a thrust-sustaining surfaceor surfaces which merge into an annular recess, or into recesses atintervals, adapted to receive the back of the die; saidthrust-sustaining surface, whether it be stationary or revolublc, beingin contact with the back of the die, which is adapted to be drawn intothe recess for the purpose of removing the die from the work at the endof the cutting operation. The thrust-sustaining surface and recess arepreferably continuous around the device, but whether continuous orinterrupted at. intervals, they have an annular relation to thedie-carrier: hence the term annular as employed in the appended claimsis to be understood as applying to either form.

Having thus described my invention what I claim as new and desire toobtain by Letters latcnt is:

1. In a thread-cutting machine, the com bination of a. work-holder and adie-carrying head having a screw-connection, radially-movable diescarried by the head, means rev lubly-mounted on the work-holderproviding thrust-snstaining surfaces which revolve with and aretraversed longitudinally by the backs of the dies as they advanceaxially, and automatic die-retracting and resetting means operatedrespectively by the feed and reverse movements of the die-carrying head,the same comprising eoopcrative cam-in trumentalities of which a pair ison the die and another pair is carried by the work-holder and has afixed h ngitudinal position. *ach pair of such instrlmientalitiesincluding at least one beveled surface.

2. n a thread-cutting machine. the conr bination of a frame providedwith an annular thrustsustaining surface which merges into a recesshaving a anrsurface, and a die provided with means for engaging saidcanrsurl'ace of said recess for the purpo t of removing the die from thework at the end of the cutting operation.

5. In a threadcutting machine, the combination of a frame provided withan annu- In testimony whereof I afiix my signalar thrust-sustainingsurface Which merges ture, in presence of two Witnesses.

into an annular recess havin cam faces, and 1 a die provided with meansfor engaging a HILAND E ARNSWVORTH' cam-faced portion of said recess forthe pur- \Vitnesses:

pose of removing the die from the work at \V. H. NULLGAUGII,

the end of the cutting operation. A. L. ROBBINS.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. G.

